KitePodModels

Models of control pods for kite power systems.

This package is part of Julia Kite Power Tools, which consist of the following packages:

Background

A kite pod or kite control unit consists of one or two electric miniature winches, that pull on two or three lines (attached to the kite) and allow to steer the kite and to change the angle of attack and thus the lift.

This software acts as controller: It has two inputs, the set values, and two outputs, the actual values.

Two P controllers are used.

The geometric nonlinearity due to the change of the effective drum diameter of the drum with the depower tape is taken into account.

Installation

Follow the instructions at Installation of Julia, using Julia 1.10 or later. Then you can add KitePodModels from Julia's package manager, by typing

using Pkg
pkg"add KitePodModels"

at the Julia prompt.

Testing

You can run the unit test suite with the following command:

pkg"test KitePodModels"

Provides

• functions to initialize the model, update the set values and read the actual values
• a function KitePodModels.on_timer() that needs to be called once per time step
• a function to convert the actual depower value into change of angle of attack

Configuration

There are two types of kite control unit models, called KCU1 and KCU2. For KCU1 the following parameters are used:

kcu:
    kcu_model: "KCU1"            # name of the kite control unit model, KCU1 or KCU2
    kcu_mass: 8.4                # mass of the kite control unit                      [kg]
    power2steer_dist: 1.3        #                                                     [m]
    depower_drum_diameter: 0.069 #                                                     [m]
    tape_thickness: 0.0006       #                                                     [m]
    v_depower: 0.075 # max velocity of depowering in units per second (full range: 1 unit)
    v_steering: 0.2  # max velocity of steering in units per second  (full range: 2 units)
    depower_gain: 3.0            # 3.0 means: more than 33% error -> full speed
    steering_gain: 3.0

For KCU2 the following parameters are used:

kcu:
    kcu_model: "KCU2"              # name of the kite control unit model, KCU1 or KCU2
    kcu_mass: 15.0                 # mass of the kite control unit                    [kg]
    kcu_diameter: 0.4              # diameter of the KCU for drag calculation          [m]
    depower_zero: 38.0             # depower setting for alpha_zero = 0                [%]
    degrees_per_percent_power: 1.0 # linear approximation                      [degrees/%]
    v_depower: 0.053  # max velocity of depowering in units per second (full range: 1 unit)
    v_steering: 0.212 # max velocity of steering in units per second (full range: 2 units)
    depower_gain: 3.0              # 3.0 means: more than 33% error -> full speed
    steering_gain: 3.0

Nomenclature

• depower: a value between 0% and 100%; zero corresponds to the power line being fully reeled-in
• rel_depower: a value between 0.0 and 1.0
• depower_offset: 23.6 # at rel_depower=0.236 the kite is fully powered [%]
• alpha_depower: the change of the angle between the kite and the last tether segment [rad]

Testing

Please, have a look at the four examples in the examples folder.

Licence

This project is licensed under the MIT License. Please see the below WAIVER in association with the license.

WAIVER

Technische Universiteit Delft hereby disclaims all copyright interest in the package “KitePodModels.jl” (models for airborne wind energy systems) written by the Author(s).

Related

• The meta-package KiteSimulators
• the package KiteUtils
• the packages KiteModels and WinchModels and AtmosphericModels
• the packages KiteControllers andKiteViewers

Documentation Stable Version Development Version

Author: Uwe Fechner (uwe.fechner.msc@gmail.com)